The trend of moving toward higher frequencies in the electronics design industry is not new, but the pace is accelerating. Whether it’s the increasing number of users at the lower frequencies of the spectrum in the communications industry or the need for higher resolution in the aerospace and defense industry, wider bandwidth availability is the key driver for moving up the frequency ladder.
Who’s Doing it?
While traditionally the drive to higher frequencies has come from the defense industry, the interest of the communications industry has increased significantly, as users have become bandwidth hogs. There is significant activity around the 80-GHz bands for point-to-point radios and cellular system backhaul.
Down to the 60s, data rates are also increasing for short-range communications, with notably personal area networking and video networking in the 60-GHz industrial, scientific, and medical (ISM) band. For short-range communications, there is now interest in 120 GHz. Commercial wireless developments such as WiGig with wireless HDMI are areas of interest due to the requirement for HD video over air.
“The ability to see quality, high-speed HD video on a mobile device without a cable is a significant driver,” says C.J. Meurell, vice president and general manager at Aeroflex. “I expect the 60-GHz market to mature over the next five years.” Companies have indeed already adopted the technology on large appliances such as TV sets, and Panasonic even put it on a smart phone.
The need for wider bandwidth availability, driven by the need for better resolution, is also driving the move to higher frequencies in the homeland security, radar, and imaging industries. “There has been talk about speeding up flows through airports by installing more sophisticated imaging systems in place. Security screening at millimeter waves is a growing area,” says Bob Buxton, product marketing manager for the General Purpose Test business unit at Anritsu. On the imaging front, the strive for finer-resolution images is driving the need to move to higher frequencies such as 94 GHz, but that can extend to 220 GHz. On the radar front, finer resolution is required to detect small targets.
“In the automotive industry, companies are also trying to design products at higher frequencies such as collision avoidance radars at around 77 GHz,” points out Roger Stancliff, chief technology officer for the Component Test division at Agilent Technologies. Other industries affected by the trend include the food industry, which uses microwave techniques to detect foreign bodies in food, and the medical industry, which is looking at how the human body responds to microwaves or millimeter waves for the purpose of medical diagnostics and treatment.
Cost, Power Consumption, And Phase Noise
Challenges vary by industry, although cost is or will be a significant issue for all over time. To build short-range wireless communications into consumer devices, the cost challenge, besides power consumption issues, needs to be overcome, which in turn impacts technical considerations.
While other industries haven’t been under the same price pressure as the communications industry, it becomes more of an issue when the size of the rollout increases. For example, the medical industry may aim to deploy devices more generally, making them available at doctor offices. Similarly, when it comes to homeland security, expanding security into facilities such as airports or to other points of interest such as railway stations or shopping malls would increase the cost challenge’s importance.
The cost challenge also trickles down to the test and measurement industry. As highlighted by Justin Stallings, product marketing manager for signal generators and power meters at Rohde & Schwarz, “while it is difficult to design a chip at a high frequency and bandwidth that is low cost, it is as hard to test it at low cost.”
In areas like homeland security and defense electronics, however, the greater challenge is to drive to certain degrees of sensitivity rather than tackle the cost challenge, at least for now. Phase noise is particularly critical in the radar industry, as it tries to detect smaller and/or slow-moving targets.